Thomas King

New York Times

Published 4:00 am, Wednesday, November 1, 2000

Thomas King, whose early research in frog embryos foreshadowed the cloning of sheep and other mammals decades later, died Oct. 25 at Johns Hopkins Hospital in Baltimore. He was 79 and lived in Alexandria, Va.

The cause was cancer, his family said.

At the Institute for Cancer Research in Philadelphia, Dr. King was investigating how cells specialize in a developing embryo when he and a colleague, Dr. Robert Briggs, devised a delicate microsurgical technique of transplanting the nucleus of a single advanced embryonic cell into an egg whose nucleus had been removed.

Their achievement, reported in 1952, showed that a nucleus could be transferred from a tadpole to a frog's egg to produce a new frog, in effect by cloning. The matter rested there, the scientific consensus being that it was impossible to duplicate the feat with genes from adult frogs.

Reports to the contrary were not authenticated until the 1960s, when Dr. John Gurdon of Britain repeatedly succeeded in cloning frogs. His results awakened the world to the implications of the procedure and inspired a spate of science-fiction accounts of human clones.

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Then, in 1981, scientists at the University of Geneva reported the first cloning of a mammal. Using cells from mouse embryos, they produced three mice that were genetically identical and cleared the way for experiments with larger mammals.

For their groundbreaking contribution, Dr. King and Briggs were awarded the Charles Leopold Mayer Prize of the Academie de Science, Institut de France, in 1972. They were the first Americans to receive the award, the academy's highest.